Roller hearth furnace



2 Sheets-Shed 1 I-Iis A torneg.

GQW. HEGEL ROLLER HEARTH FURNAGE June 1, 1937.

F .1ed Aug. 5, 1956 10 heavy load on the driving mechanism. It is an Patented `lune 1, 1937 Parri-:rrr ori-*ics ROLLER HEARTH FURNACE George W. Hegel, Scotia, N. Y., assignor to GencralV Electric York Company, a corporation of New Application August s, 193e, semina. 94,380

6Claims.

tMy invention relates to roller hearth furnaces of the type which is adapted to contain a gas atmosphere. Furnaces of this type having a series of driven rolls extending through the-furnace wall to the driving mechanism heretofore have been provided with stuiiing boxes for the separate rolls to prevent the escape of the gas employed in the furnace. Where a furnace includes manynriven rolls the combined friction of l the many stuning boxes imposes an objectionably object of my invention to provide an improved construction4 of roller hearth furnace which while Veffective to prevent the loss of. gas therefrom around the rolls avoids the necessity of employing stuiiing boxes and hence reduces the load on the driving mechanism.

My invention will be better vunderstood from' the followingdescription taken in connection with the accompanying drawings, and its scope will ,bepointed out in the appended claims.

vReferring to the drawings, Fig. 1 is a Sideview` of a roller hearth furnace embodying my invention; Fig. 2 is a. cross-sectional view of the same taken on the line 2-2 -of Fig. -1- and drawn kto a larger scale; Fig. 3 is a cross-sectional view taken on the line 3 3 of Figi; Fig. 4 is an en.-

` larged plan of a. detail of the furnace shown in Fig. i; Fig. 5 is a side iview partlyvin section of the left hand end of the gas tight casing shown inFig. 1; Fig.6isa

' on the line 6-6 of Figf 5; Fig. '7 is a longitudinal sectional view taken throughthe central portion .t The furnace lcomprisesthe I of heat insulating material of Fig. 5; Fig. 8 is a detail view of the gastlght casing at the right hand end of Fig. 1; Fig. 9

kis a cross-sectional view taken on the line 9--9 of Fig. 8;. Fig. 10 is a longitudinal cross-sectional view through the 'central portion of Fig. 8; and Fig. 11 is a Vsectional view taken on the line II-II -of Fig. 10. Y

outer sheet metal casing 2'within whichis a relatively thick layer having the lining I of refractorymaterial as is usual in furnaces o1' this type. 'I'he heating chamber so formed is normally closedvat each end of the furn'ciin order to retain the gas which constitutes the gas atmosphere, suitable provision being made for passing into and out of the furnace the material to be treated therein. Heat may be supplied to the heating chamber of the furnace by any desired means, the chamber in this case being represented as being heated by the several electricA c'ross-sectional view taken is mounted the idler I2 andy sprocket I3. Ac-

ported upon a series of parallel rolls 6 which pass through suitable openings in the furnace walls on opposite sides of the heating chamber, the ends of the rolls being reduced in diameter and supported in lbearings outside of the walls.` The 5 bearings l at one side of the furnace, are secured directly and in a gas tight manner to the outer casing 2 and are constructed with closed ends thereby to avoid the necessity of using stuiling boxes to prevent the loss at those points of the gas forming the atmosphere in the furnace.

At the `other side of the. furnace the reduced ends of the rolls are somewhat longer and on those ends suitable means are provided by which the rolls are rotated. An example of such means is 15 shown in the drawings as comprising the sprockets 9 secured to the reduced ends of the rolls and engaging with those sprockets is the endless chain In. For producing a desired tension in the chain I have shown a well known form f ten- 20 sion adjusting means Il at one end f the chain loop, see Figs. and 7. At the opposite end of the loop I have shown theidler sprocket l2 and ,the drive sprocket I3, see Figs; 10 and 11which through the drive shaft I connects with the drive sprocket I5. The latter sprocket connects through the chain I6 with a Sprocket on the counter shaft I'I` which is driven through the chain I8 from the motor I9 through the gear reducing mechanism.

In order to avoid the use of stuing boxes at those ends of the rolls at which the drive is connected I provide the furnace with the gas tight casing 22 which encloses the ends of the rolls, the sprockets thereon, and the drive chain'assoelated therewith.. This casing comprising an enclosure formed by the upper and lower plates 23 and 24 respectively, the channel 25 and .the angle 26 as 'shown in Figs. 5, 6, and 7. It also comprises the several members 2l which are detachably secured in a gas tight manner to the outer face of the channel 25 over openings therein through which the ends of the rolls extend. They serve the double purpose of'forming bear` ings forthe rolls and preventing the escaperof gas through the bearings. The .casing thus formed is closed at one end bythe end plate '28 and at the other end by the housing 29 in which cordingv to this construction there is only one point at which a stuffing box is required and that is at the point where the drive shaft Il passes through the housing 29, the stuiiing box at this point being represented at 3U. Shaft I4 is Journaled in two bearings one of which is repre'- 55 sented `at 3i within the housing 29 and the other at 32 carried by the frame 33.

vends enclosed by a gas tight casing shown at 36 which functions in the same manner as the abovedescribed casing 22. f

In accordance with the construction described above, the members 21 which constitute both the bearings for the rolls and portions of the enclosing gas tight casing are arranged at the maximum distance from the source of heat in the furnace whereby they may operate as cool as possibleand are also easilyvdetached for inspection and replacement.

readily accessible and Inasmuch as the bearing members at the other ends of the rolls are of a similar construction to themembers 21 and are secured directly to 25'the furnace, it will be seen that I am able to dispense entirely with the use of stuiiing boxes on the rolls and thereby to drive the rolls with a minimum amount of friction loss, yet the gas atmosphere in the furnace is retained without loss around the rolls. I have chosen the particular embodiment described above as illustrative of my invention and it will be apparent that various modifications may be made without departing from the spirit and scope of my invention which modiiications I aim to cover by the appended claims.

"What I claim is new and desire to secure by Letters Patent of the United States: 1. Aroller hearth furnace constructed to contain a gas atmosphere and having a plurality of rolls extending therethrough, means connected with said rolls for rotating the same and a gas tight casing secured to a wall of the `furnace and enclosing corresponding ends of said rolls and said rotating means.

y ber for said rolls 2. A roller hearth furnace constructed to contain a gas atmosphere and having a plurality of rolls extending therethrough, a common means for rotating said rolls and a gastight casing secured to a wall of the furnace for enclosing said rotating means and the corresponding ends of Asaid rolls.

3. A roller hearth furnace constructed to contain a gas atmosphere and having a plurality of rolls extending therethrough, means connected with saidrolls for rotating the same, bearings for said rolls and means for preventing the escape of said atmosphere around said rolls comprising a casing cooperating with said bearings to form a gas tight enclosure for said rotating means and the corresponding ends of said rolls.

4. A roller hearth furnace constructed to contain a gas atmosphere and rolls extending therethrough and having portions extending beyond a wall thereof, a driving memconnected with said extending portions, means for supporting said rolls and means secured tight enclosure for the extending portions of said rolls and said driving member. I f

5. A roller hearth furnace constructed to contain a gas atmosphere and having a plurality of rolls extending therethrough and having p0rtions extending beyond a wall thereof, a single member connected with the extending portions oi' said rolls/for rotating the same, and a gas tight 4casing secured to said wall and enclosing said rolls and said member, said casing having bearings secured thereto for said rolls.

6. A roller hearth furnace vconstructed to contain a gas atmosphere and having a plurality of rolls having end portions extending exteriorly of a wall of the furnace, sprockets on said end portions, a drive chain engaging said sprockets, a gas tight casing comprising an enclosure for said portions, sprockets and chain and bearing members for said rolls having closed ends secured to the exterior of said enclosure.

vciaoacas: w. HEGEL.

having a plurality of to saidwail, and forming a gas 

